Apparatus for and method of lapping similar articles



April 15 1924. I 1,490,391

W. E. HOKE APPARATUS FOR AND METHOD OF LAPPING SIMILAR ARTICLES FiledApril 27, 1921 method of grinding or lapping a plurality of similararticles arranged in two sym- Patented Apr. 15, 1924 UNITED "srArEs1,490,391: PATENT QFFlC-E.

WILLIAM E. noxiaor sr. LOUIS, MISSOURI, AssmNoB. 'ro PRATT & WHITNEYcom- PANY, or NEW YORK, N. Y, A CORPORATION or'NEw JERSEY.

APPARATUS FOR AND METHOD OF LAPPING SIMILAR ARTICLES.

Application filed April 27, 1921. Serial No. 464,791.

' vented certain new and useful Improvements in Apparatus for andMethods of Lapping Similar Articles, of which the following is aspecification.

This invention relates to an apparatus for and method of grindingsimilar articles so that they may be simultaneously finished to apredetermined definite and precise dimension. More particularly thisinvention relates t0 anapparatus for and method of grinding a pluralityof similar precision ages having opposite plane parallel end taces atpredetermined identical distancesv apart.

An object of the. present invention is toprovide an improved apparatusfor and a metrical groups, so that the articles, such as precisiongages, may be simultaneously ground to predetermined identical dimen-'sions and be provided with opposite plane parallel end faces.

I accomplish the above objects of the invention by grouping the gages,or other articles, to be ground in two groups or'rings, one within theother each group or ring containing a .plurality,'preferably twelve ormore,'of the articles to be ground.

The outer group of articles is mounted concentric with a spider whichisdirectly moved relative to the surfaces of the lapsby suitable actuatingmeans. The inner group of articles is mounted in an independent spidersuitably supported within the first, .or outer,spider." To provide meansfor moving the inner group relative to theouter group, I preferablyprovide serrations, or teeth, on the contacting surfaces of the innerand outer spiders. These, in connection with the movements imparted tothe outer; spider, urg the inner spider toprotate relative to the-outerspider so that the. relative disposition of the inner'and outergroup ofarticles is 7 constantly and-wautomatically being changed. i

' One feature which enables .me to make 7 similar articleslravingopposite plane parallel-faces at predetermined'identical distances apartis that'the articles to 'be ;made having their 'end 'faces so "formedare arrangedas above described and are disposed and operated betweenplane surfaced laps, one of the laps being ad ustable as to parallelismrelative to the other.

Theinvention is preferably carried out in an apparatus having twospiders, or carriers, in which the articles to be ground are mounted.Each of these spiders, in theembodiment of the invention selected forillustration, has a single ring or group of openings equally spaced fromeach other and equally spaced about the center of the spider. Withineach of these openings or orifices in the spiders, one of the articlesto be ground is located,-the opening being such that the article may befree to rotate about its individual center or axis. V p

In order to accomplish the necessary operative movements between thegroups of articles and the laps, I preferably provide the outerperiphery of the spider or carrier with gear teeth, extending entirelyaround its periphery which are in engagement with small pinions suitablymounted at the ends of-short cranks which may be rotated by any suitablemeans. Preferably three of these cranks and pinions are provided, all oflaps may be substituted for the mechanismv shown.; 1 M

As the inner spider is smaller than the outer one and has fewerserrations, the effect of the lapping movement s imparted to the outerspideriwill be to force the inner spider to rotate with it. Also theinner spider will be given a slight preces'sional or advancing movementrotatively relative to the outer" spider. In this way a continuousprogressive interchange takes place between the two, groups of articleswhile both groups of; articles, partake, of the r eciprocatory lappingmovements imparted to the outer spider. l

lie bei 'anii aha objectsfin vise,

my invention consists .cinjthe features'of construction andoperation setforth in the 1,

following specification and illustrated in the accompanying drawing.

In the accompanying rawing annexed hereto and forming a part of thisspecification, I have shown my invention embodied in a gage grinding orlapping machine but it will be understood that the invention can beotherwise embodied and that the drawing is not -to be construed asdefining or limiting the scope of the invention, the claims appended tothis specification being relied upon for that purpose.

In the drawing:

Figure 1 is a plan view of an apparatus for carrying out the presentinvention, the upper lap being removed. i

Fig. 2 is a vertical sectional view of the apparatus taken on line 2-2of Fig. 1.

-In the above mentioned drawing, I have shown but one modification ofthe invention which is now deemed preferable, but it is to be understoodthat changes and modifications ma be made within the scope of theappende claims without departing from the spirit of the invention.

Briefly, my invention in its broadest aspect comprises the followingprincipal elements; first, a lower lap mounted rigidly in position orforming the base of a lappin machine or device; second, a lap positionabove the first lap and adapted to be held from rotation, but arrangedso that it may rest on and adjust itself relative to the articles beingground; third, an outer spider having a plurality of openings preferablyat e ual distances from each other and dispose symmetricallyabout itscenter;

fourth, a second spider within said first.

The present lnvention is a modification,

or improvement of the invention shown in my copending applications,namely, Serial No. 242,482 filed June 28, 1918, and Serial No. 458,280,filed April 4:, 1921, to which reference may be had for a furtherdescription of the lapping machine.

Referring more in detail to the figures of the drawing, at 10 is shown alower lap adapted to be mounted on a suitable sup ort and normally heldfrom rotation thereon. At 11 is shown an upper lap mounted incoolperating'position directly above the lower ap 10. Guides 12 securedto the lower lap extend through suitable guideways 13 provided on theupper lap so that the upper lap 11 is held from rotation relative to thelower lap 10 but is free to adjust itself as to parallelism with thelower lap and relatively to the articles being ground. The adjacentsurfaces 15 and 16 of the laps 10 and 11 are suitably charged with anabrasive compound. Disposed between the adjacent surfaces of the laps 10and 11 is an outer spider 20. This,-preferably, is provided with gearteeth 21 on its periphery engaging pinions 22 mounted at the end ofshort cranks 23 which are suitably fastened to shafts 24. Preferably,three of these pinions 22 are provided. Rotation of the shafts 24rotates the cranks 23 and the pinions 22 secured thereon, thus givingthe outer spider 20 a reciprocatory movement due to the crank action andalso a slow precessional movement about its own center due to theengagement of the teeth 21 with the pinions 22. Suitable supports 25 aremounted below the cranks 23 to support the spider 20 in placeapproximately midway between the adjacent surfaces 15 and 16 of the laps10 and 11. Arranged about the outer spider 20, preferably in a circle,are orifices 30 large. enough to loosely retain one of the articles tobe lapped.

Within the outer spider 20 is another spider member 35 which has anothergroup or circle of orifices 36 of the same size as the orifices 30, inthese latter orifices another group of articles to be lapped may bemounted.

Preferably, 'the outer periphery of the spider 35 and the inner surfaceof the outer spider 20 are serrated or rovided with gear teeth. These,as shown in the drawing, may be formed of circular arcs of suflicientdiameter to provide amp-1e room for the orifices 20 and 36 in each toothor ser ration.

To support the inner spider 35 in place within the outer spider 20struts 37 may be provided suitably fastened to the lower surface ofspider 35 and adapted to rest on the upper surface of lap 10.

It will be seen from the above construction that when the outer spider20 is reciprocated and slowly rotated, the inner spider 35 will also bereciprocated and rotated by reason of the fact that one side of theinner spider 35 will always have its teeth in engagement with some ofthose in the outer s ider 20. The effect of this is to continuous yrotate the inner spider 35 relative to the outer spider 20 as well as tore cifprocate the inner spider. As the number 0 serrations or teeth 36in the inner spider 35 is less than the number in the outer spider 20,the effect will be that the teeth on tween the innerandouter spiders.arrangement, therefore, constantly changes the disposition of thearticles to be lapped This has the efiect of varying or inter changingthe blocks continuously and auto matically and avoids the necessity ofmanually tra-nsposing the blocks to get a very high degree of identitybetween the articles being lapped. The construction above described,however, isadapted to permit manual interchanging if that is thoughtdesirable, either by interchanging the relative positions of thearticles within their own groups or rings or transposing the blocksbetween the inner or outer rings.

With orifices such'as 30 and 36 provided in each serration or tooth ofthe inner and outer spider's, the articles being lapped pass moreclosely over identical parts of the lapping surfaces so that the lappingefiect on the inner group of articles is the same as that on the outerring and thus avoids any inaccuracies in the dimensions of the articlescaused by the different sections of the laps passed over by the innerblock be ing more irregular or inaccurate than those passed over by theouter group of blocks.

What I claim is:

1. The method of making articleshaving opposite plane parallel endfaces, which comprises grouping said articles in two symmetrical groups,one within the other, said groups being movable relative to the other,and operating said articles while contained in said groups between andin contact with adjacent plane surfaces of a pair of laps.

2. The method of making articles having opposite. plane parallel endfaces, which comprises grouping said articles in two symmetrical groups,one within the other, and continuously and uniformly moving said groupsrelative to the other while operating said articles contained in sandgroups between and in contact with adjacent plane surfaces of a pair oflaps.

3. The method of makingarticles having opposite plane parallel endfaces, which comprises grouping said articles in two symmetrical groups,one within the other, said groups being movable relative to the other,-operating said articles while contained in said groups between and incon.- tact with adjacent plane surfaces of a pair of laps, andcontinuously rotating one group relative to the other during .operation.

4. The method of making articles having opposite plane parallel endfaces, which comprisesgrouping said articles in two circular groups, onewithin the other, said groups being movable relative to the other,reciproeating and rotating said articles while contained in said groupsbetween and in contact with adjacent plane surfaces of a pair of laps,and simultaneously rotating one group at a diiierent rate than theother.

5. An apparatus for making similar articles having opposite planeparallel end faces,

comprising in combination, a pair of, laps having adjacent plane lappingsurfaces adapted to contact with the articles being ground, a spideradapted to operate therebetween, said spider having a. plurality ofarticles symmetrically grouped therein, and a second s ider within therst spider movable relatively thereto, said second spider also having aplurality of articles symmetrically grouped t-herein.

6. An apparatus for making similar articles having opposite planeparallel end faces comprising in combination,.a pair of laps havingadjacent plane lapping surfaces adapted to contact with the articlesbeing ground, a s ider adapted to operate therebetween, sai spiderhaving a plurality of articles symmetrically grouped therein, a secondspider within the first spider and movable relatively thereto, saidsecond 'spider also having a pluralityvof articles symmetrically groupedtherein,'-and connections between said spiders whereby said innerdspideris rotated relative to the outer spi er. Y

7. An apparatus for making similar articles having opposite planeparallel end faces, comprising in combination, a pair of laps havingadjacent plane lapping surfaces adapted to contact with the articlesbein ground, a spider adapted to reciprocate an rotate therebetween,said spider having aplurality of articles symmetrically ouped therein, asecond spider within t e first spider and rotatable relatively thereto,said second spider also having a plurality of articles symmetricallygrouped therein, and means to rotate saidinner s ider 'at a differentrate than the outer sp1der.

8. An apparatus for making similar articles having-opposite planeparallel end faces comprising in combination, a pair of laps havingadjacent plane lapping surfaces adapted to contact with the articlesbein ground, a spider adapted to reciprocate an rotate therebetwecn,said spider having a plurality of articles symmetrically grou edtherein, and a second s ider within the first spider having a lura ityof articles symmetrically groupe therein adapted to intermesh with saidvfirst spider whereby the renot ciprocatory and rotary movements of saidouter spider rotate said inner spider relative to the outer spider.

9. An apparatus for making-similar'articles having opposite planeparallel end faces, comprising in combination, a pair of laps havingadjacent plane lapping surf adapted to contact with the articles beingground, a spider adapted to reciprocate an rotate therebetween, aplurality of articles symmetrically grouped therein, gear teeth on saidspider adjacent said articles, a second spiderwithin the first spiderhaving a.

plurality of articles symmetrically grouped therein, and ear teeth onthe outer periphery of said inner spider, whereby reciprocation androtation of said outer spider re- )0 ciprocates and rotates said innersplder over approximately the same portions of said laps passed over bythe articles in the outer group.

In testimony whereof, I hereunto afiix my 15 signature.

WILLIAM E. HOKE.

